This invention relates to a charge motion control valve, and more particularly, to a charge motion control valve which is adapted for use within an internal combustion engine, and which provides for improved engine operation and stability during cold start operating conditions.
Charge motion control valves (xe2x80x9cCMCVsxe2x80x9d) are used within internal combustion engines in order to improve the flow of air and fuel into the engine""s cylinders. A CMCV is typically and operatively disposed within an intake port of a vehicle engine xe2x80x9cupstreamxe2x80x9d from a fuel injector. The CMCV is effective to alter the flow of air into the cylinder during certain vehicle operating modes (e.g., during relatively low engine speed and load conditions), and is effective to create turbulence within the cylinder, thereby improving combustion within the cylinder.
One type of CMCV is designed for use in combination with a xe2x80x9cSiamesexe2x80x9d type intake port which includes a main air intake port that splits or xe2x80x9cbranchesxe2x80x9d into a pair of separate ports that communicate with one of the engine""s cylinders. This type of CMCV is typically and operatively disposed in relative close proximity to the location where the main intake port splits and is designed to alter the flow of air into each of the port branches. Some of these prior CMCVs, commonly referred to as xe2x80x9cswirlxe2x80x9d type CMCVs, are typically designed to substantially xe2x80x9ccoverxe2x80x9d one side of the main air intake port, thereby preventing air from entering one of the branches. In this manner, the CMCV provides a xe2x80x9cfuel richxe2x80x9d mixture within that branch that is subsequently discharged into the cylinder and combusted. Additionally, this type of CMCV covers only a portion of the other side of the main air intake port, effective to allow a substantial amount of air to flow into the other branch and to create a xe2x80x9cfuel leanxe2x80x9d mixture in that branch that is subsequently discharged into the cylinder and combusted along with the fuel rich mixture. This flow of air into the cylinder creates a swirling effect or turbulence which causes the fuel rich mixture and fuel lean mixture to combine and provide improved combustion. In this manner, the CMCV increases engine efficiency and decreases harmful emissions.
While these prior CMCVs provide the foregoing benefits, they suffer from some drawbacks which adversely effect the efficiency of the engine during certain operating conditions. For example and without limitation, during cold start operating conditions (i.e., when the vehicle is being started after being exposed to relatively cold temperatures), fuel often condenses on the intake valves due to a lack of heat. Because this type of prior CMCV substantially blocks air from flowing into one of the port branches, condensed fuel often remains on the intake valves within that branch and/or enters the cylinder as a liquid stream and is thus not properly combusted within the cylinder. This undesirably leads to oil degradation, waste fuel, and increased hydrocarbon emissions.
Another prior type of CMCV, commonly referred to as a xe2x80x9ctumblexe2x80x9d type CMCV, is used to create a xe2x80x9ctumblingxe2x80x9d flow of air into the cylinders. This type of CMCV provides substantially symmetrical passages for air to flow on each side of the valve. Hence, this type of CMCV provides a substantially similar air/fuel mixture and airflow within each branch port. While this type of CMCV substantially prevents condensation from remaining on the intake valves, it does not cause the desired swirling and mixing of the fuel and air provided by the xe2x80x9cswirlxe2x80x9d-type control valves, and therefore does not provide the concomitant fuel economy and emissions benefits.
There is therefore a need for a new and improved charge motion control valve which is adapted to provide improved mixing of air and fuel within a combustion cylinder during cold start conditions.
It is a first object of the invention to provide a charge motion control valve which overcomes at least some of the previously delineated drawbacks of prior charge motion control valves.
It is a second object of the invention to provide a charge motion control valve for use in combination with an internal combustion engine having xe2x80x9cSiamesexe2x80x9d type fuel intake ports.
It is a third object of the invention to provide a charge motion control valve which provides for improved engine stability during cold start operating conditions.
It is a fourth object of the invention to provide a charge motion control valve which is effective to cause condensed fuel to be removed from intake valves and to be properly mixed and combusted within a cylinder.
According to a first aspect of the present invention, a charge motion control valve is provided. The charge motion control valve is adapted for use within an engine of the type including an air intake port which branches into a first and a second intake port which communicate with a cylinder, and a fuel injector which injects fuel into the first and second intake ports. The charge motion control valve is operatively disposed in the air intake port in relative close proximity to the first and second intake ports and includes a first half which forms a first unrestricted area, effective to allow a first amount of air to enter into the first intake port, and a second half which forms a second unrestricted area which is smaller than the first unrestricted area and which is effective to allow a second amount of air to enter into the second intake port, the first and second amounts of air being effective to carry the fuel into the cylinder and to create turbulence within the cylinder.
According to a second aspect of the present invention, a method is provided for controlling the flow of air within an air intake port of the type including a primary port which branches into a first port containing a first amount of fuel and a second port containing a second amount of fuel, the first and second ports being selectively and fluidly connected to a cylinder. The method includes the steps of: directing a first amount of air into the first port, effective to substantially vaporize the first amount of fuel; directing a second amount of air into the second port, the second amount of air being greater than the first amount of air, and being effective to substantially vaporize the second amount of fuel and to cooperate with the first amount of air to create turbulence within the cylinder.
These and other features, aspects, and advantages of the invention will become apparent by reading the following specification and by reference to the following drawings.